[RPP] Minor performance fix for entity map update function

This function is at the top of the hot path for loading a trace. The
real time being spent is within third-party-web's
getDomainFromOriginOrURL. This CL is a very minor improvement, to reduce
repeated map lookups (.has followed by .get).

Bug: 40278532
Change-Id: I6025590061f2327f29296efd56e9de4b8c24c98e
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6219689
Commit-Queue: Connor Clark <[email protected]>
Reviewed-by: Paul Irish <[email protected]>

Author: Connor Clark

front_end/models/trace/handlers/NetworkRequestsHandler.ts

@@ -486,7 +486,7 @@ export async function finalize(): Promise<void> {
     requestsByTime.push(networkEvent);
     requestsById.set(networkEvent.args.data.requestId, networkEvent);
     // Update entity relationships for network events.
-    HandlerHelpers.updateEventForEntities(networkEvent, entityMappings);
+    HandlerHelpers.addEventToEntityMapping(networkEvent, entityMappings);
     const initiatorUrl = networkEvent.args.data.initiator?.url ||
         Helpers.Trace.getZeroIndexedStackTraceForEvent(networkEvent)?.at(0)?.url;
     if (initiatorUrl) {

front_end/models/trace/handlers/RendererHandler.ts

@@ -356,7 +356,7 @@ export function buildHierarchy(
       // Update the entryToNode map with the entries from this thread
       for (const [entry, node] of treeData.entryToNode) {
         entryToNode.set(entry, node);
-        HandlerHelpers.updateEventForEntities(entry, entityMappings);
+        HandlerHelpers.addEventToEntityMapping(entry, entityMappings);
       }
     }
   }

front_end/models/trace/handlers/helpers.ts

@@ -20,20 +20,16 @@ export interface EntityMappings {
   eventsByEntity: Map<Entity, Types.Events.Event[]>;
 }
 
-export function getEntityForEvent(event: Types.Events.Event, entityByUrlCache: Map<string, Entity>): Entity|undefined {
+export function getEntityForEvent(event: Types.Events.Event, entityCache: Map<string, Entity>): Entity|undefined {
   const url = getNonResolvedURL(event);
   if (!url) {
     return;
   }
-  return getEntityForUrl(url, entityByUrlCache);
+  return getEntityForUrl(url, entityCache);
 }
 
-export function getEntityForUrl(url: string, entityByUrlCache: Map<string, Entity>): Entity|undefined {
-  if (entityByUrlCache.has(url)) {
-    return entityByUrlCache.get(url);
-  }
-  const entity = ThirdPartyWeb.ThirdPartyWeb.getEntity(url) ?? makeUpEntity(entityByUrlCache, url);
-  return entity;
+export function getEntityForUrl(url: string, entityCache: Map<string, Entity>): Entity|undefined {
+  return ThirdPartyWeb.ThirdPartyWeb.getEntity(url) ?? makeUpEntity(entityCache, url);
 }
 
 export function getNonResolvedURL(
@@ -145,15 +141,18 @@ function makeUpChromeExtensionEntity(entityCache: Map<string, Entity>, url: stri
   return chromeExtensionEntity;
 }
 
-export function updateEventForEntities(entry: Types.Events.Event, entityMappings: EntityMappings): void {
-  const entity = getEntityForEvent(entry, entityMappings.createdEntityCache);
-  if (entity) {
-    if (entityMappings.eventsByEntity.has(entity)) {
-      const events = entityMappings.eventsByEntity.get(entity) ?? [];
-      events?.push(entry);
-    } else {
-      entityMappings.eventsByEntity.set(entity, [entry]);
-    }
-    entityMappings.entityByEvent.set(entry, entity);
+export function addEventToEntityMapping(event: Types.Events.Event, entityMappings: EntityMappings): void {
+  const entity = getEntityForEvent(event, entityMappings.createdEntityCache);
+  if (!entity) {
+    return;
   }
+
+  const events = entityMappings.eventsByEntity.get(entity);
+  if (events) {
+    events.push(event);
+  } else {
+    entityMappings.eventsByEntity.set(entity, [event]);
+  }
+
+  entityMappings.entityByEvent.set(event, entity);
 }